NEW YORK — For evidence that digital information, once set free, cannot be controlled, consider the steamy video of Brazilian supermodel Daniela Cicarelli making out with her boyfriend on a Spanish beach and in the water just off shore.

The couple persuaded a Brazilian court last fall to force the video-sharing site YouTube to remove copies, but other users simply resubmitted the video through their free accounts.

Earlier this month, Internet service providers in Brazil, responding to the judge's order, briefly blocked access to YouTube entirely. But by then other Web sites already had the video, and many in Brazil even had stored personal copies on their computer hard drives.

Safekeeping information — video, photographs, documents — will become even tougher with the emergence of additional "Web 2.0" services designed for users to easily share data. Society may have good reasons — such as privacy, security or taste — for wanting to keep the lid on some types of information, but it only takes one individual to overrule that desire.

"There are more and more ways to distribute information, but very few new approaches to keeping information secret," said Steven Aftergood, senior research analyst at the Federation of American Scientists' Project on Government Secrecy. "Paradoxically, the attempt to suppress information often tends to draw greater attention to it, so a government agency or an unhappy celebrity or anyone else may decide that challenging disclosure is counterproductive."

Indeed, the Cicarelli clip became even more popular after the YouTube ban made headlines worldwide, and users in Brazil and beyond posted it to a slew of other Web sites not subject to the Brazilian court order. Faced with international outcry, the judge ultimately lifted his YouTube ban.

But the Cicarelli video is hardly the only example of information circulating out of control.

Iraqi authorities released official footage of Saddam Hussein's Dec. 30 hanging, but cell-phone video taken by a witness quickly made the rounds online, this one showing guards taunting Saddam in the final moments of his life. One copy at Google Inc.'s main video site had been viewed more than 15 million times by Tuesday. The clip also was available through Revver Inc. and Google's YouTube.

Last summer, in a gesture to researchers, Time Warner Inc.'s AOL released the Internet search terms that more than 650,000 of its subscribers had entered over a three-month period. Senior executives quickly pulled the data, saying the release had not been properly vetted, but copies were already circulating and Web sites have even been created specifically to query that database.

And a few years ago, a hacker broke into Diebold Inc.'s servers using an employee's ID number and copied documents, some of them raising security concerns about the company's electronic-voting machines. Diebold unsuccessfully sued to have copies removed from other Web sites.

The Internet makes broad dissemination quick and easy. And because digital copies are exact copies, details don't get lost or misstated in retellings the way they might have before.

Tools for producing digital evidence are also more broadly available. The unauthorized Saddam video might not have been possible a few years ago without cell phones and digital cameras that can record video — a standard feature these days.

The Cicarelli video came from an old-fashioned paparazzo but sites like YouTube allow more people to watch. Controls to limit copying are easily defeated using third-party software for converting Flash video into files that can be stored and passed around.

Even the stanchest advocates of data free-flow worry about the ease of distribution.

"There are publications that can be an act of aggression, it can be part of a vendetta against an individual, or it can be an act of incitement against a hated minority," Aftergood said. "There are reasons why the best, most reputable media outlets have editors. With the ease of publication, today we are losing some of that editorial filter."

John Palfrey, a professor of Internet law at Harvard University, said the onus now is on individuals to "be more accountable in terms of what they do on the Internet, just as they are in everyday life. Some sense that the Internet is a lawless zone, and that's not a good thing."

But on balance, they say, the benefits of data flow outweigh any harm.

Companies, publicists and others have sometimes tried to stuff information back into the bottle, often fruitlessly. Steve Jones, a communications professor at the University of Illinois at Chicago, suspects that many of them use the courts to send a message to other would-be distributors.

"It serves more as a deterrence than as a remedy," Jones said. "It's preposterous to think that once information leaks onto the Internet, you could in fact go out and collect it all and remove it."

There are, of course, exceptions. Late last year, the government shut down a Web site containing millions of pages of documents seized in Iraq after questions were raised about whether it provided too much information about making atomic bombs.

"No one thought to copy and repost the entire database," Aftergood said, adding that individuals have succeeded in reassembling only "isolated documents."

But for the most part, a better approach is to keep the information from disseminating in the first place.

Many secret government documents remain classified despite occasional leaks. Companies successfully guard most of their software code, secret soft-drink recipes and other intellectual property. Apple Inc. Chief Executive Steve Jobs made a splash last week with details on a sleek new iPod-cell phone combination, even though the iPhone had been rumored for months.

And on Monday, Iraqi authorities showed reporters official, soundless video of two hangings — one severing the head of Saddam's half-brother — but refused to otherwise release the video for public broadcast.

People determined enough will often find ways to break controls, however.

A Norwegian teen became a hero to hackers when he posted software to crack the encryption used on most DVD movies to prevent illegal copying. And software to prevent the unauthorized copying or forwarding of company data can be easily defeated with a digital camera.

As Cicarelli and her boyfriend may have learned, there's only one surefire way to keep paparazzi video and information on them from circulating online: Don't make out in public.